Present practice for cleaning the die surfaces of sheet metal stamping presses is to stop the press line periodically during a production shift, separate the dies and then manually wipe the die surfaces to remove waste particles therefrom. Such practice presents a production line problem in that the line must be shut down for a time period to allow for such wipe-down. Another problem is that such manual wipe-down depends in part upon the care and diligence of the wiper to remove all waste particles. If the dies are not wiped perfectly clean subsequent part production can be dinged or dimpled by dirt particles remaining on the dies.
In addition to manual wiping it is known to provide apparatus for cleans dies automatically. The known automatic cleaning system is set-forth in U.S. Pat. No. 3,799,178 wherein the die is a specialty die for extruding ceramic materials. The cleaning step is performed by directing high pressure spray of cleaning material such as oil, water or a slurry of either mixed with solvent and a suitable powdered cleaning material. Such systems require an automated fluid circulation and distribution system which are not normally found on existing sheet metal stamping machines.
It is also shown in West German Offenlegungsschrift No. DT23 42 170 dated Feb. 27, 1975, that dies can be cleaned of pulverized glass used as the lubricating medium. In particular, a disc composed of mica with at least 90% of the water of crystallization removed and containing 10-15% absorbed metal salts is included on the die to avoid the buildup of glass lubricant on the die surfaces. The discs are attached to the stamping head and are present during the pressing operation. The inserts do not provide for removal of metal slivers, dirt or other waste particles generated during the stamping operation.